JPH0673582B2 - Cloth edge copying sewing machine capable of deciding cloth placement state - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth edge sewn sewing machine, and more particularly to detection of a mounting state of a work cloth on a sewing machine bed.

2. Description of the Related Art A cloth edge copying sewing machine is already known in Japanese Patent Laid-Open No. 61-257675. This is a cloth feeding device for transferring the work cloth in a predetermined transfer direction in synchronization with the vertical movement of the sewing needle, and a sewing needle in the lateral direction intersecting the predetermined transfer direction at least temporarily while the sewing needle is located above the sewing machine bed. A cloth detector having a predetermined relative positional relationship and movable in the lateral direction to detect the cloth edge of the work cloth extending in the predetermined transport direction, and driven to change the lateral position of the cloth detector. And a scanning control means for driving the control motor based on the detector signal from the cloth detector.

In this type of sewing machine, it is often necessary to detect whether the work cloth is placed on the right side or the left side of the needle drop point on the sewing machine bed. For example, it is predetermined whether the formation position of the seam with respect to the cloth edge of the work cloth is on the left or right side, and if the cloth edge is detected by the cloth detector, the sewing needle is detected by the cloth detector. When the work cloth is positioned at a predetermined distance in a predetermined direction from the end position, it is necessary to place the work cloth on the predetermined side.

Problems to be Solved by the Invention However, it is possible that an unfamiliar operator places the work cloth in a state different from the predetermined placement state. In this case, even if the sewing needle is positioned on the non-working cloth side from the cloth end, and the sewing machine cannot perform the copy sewing, the sewing machine starts execution of the copy sewing and wastes time. And sewing thread will be spent. Therefore, it is necessary to notify the operator of the abnormality of the placement state or stop the operation of the sewing machine before the copy stitching is executed.

Further, it is conceivable that the copy stitch can be performed regardless of the placement position of the work cloth, but in this case as well, it is necessary to determine the placement state of the work cloth before execution of the copy stitch. .

Means for Solving the Problems In order to solve this problem, the present invention, as shown in FIG. 1, includes a cloth edge copying sewing machine including a cloth feeding device, a cloth detector, a control motor, and a copying control means. In (a) scanning means for driving the control motor before execution of the copy stitch in order to obtain the maximum value and the minimum value of the detector signal from the cloth detector,
(B) Position signal generating means for issuing a position signal relating to the lateral position of the cloth detector, and (c) a first storage section for storing the position signal generated when the maximum detector signal is obtained and a minimum. A memory having a second memory for storing the position signal generated when the value detector signal is obtained, and (d) a magnitude relationship between the two position signals respectively stored in the first and second memories. And a determination means for determining whether the work cloth is placed on the left or right side with respect to the drop point of the sewing needle.

The control motor may move the cloth detector together with the needle in the lateral direction, or may move only the cloth detector.

Further, even if the position signal generating means takes out the position signal supplied to the control motor by the scanning means and supplies it to the memory, it detects the actual position of the cloth detector like a potentiometer and responds to the position. The position signal may be supplied to the memory.

Action Before execution of the copy stitching, the scanning means drives the control motor to change the lateral position of the cloth detector, and the cloth detector outputs the minimum detector signal when it faces the work cloth. While outputting, the detector signal with the maximum value is output when facing the part which is not the work cloth. At this time, when the position signal generating means generates a position signal whose magnitude sequentially increases or decreases in accordance with the position of the cloth detector, the maximum detector signal is obtained in the first storage section of the memory. Is stored, and the position signal when the minimum detector signal is obtained is stored in the second storage unit. That is, the first storage unit stores the position signal indicating the non-working cloth side, and the second storage unit stores the position signal indicating the working cloth. Therefore, for example, when the cloth detector is displaced from left to right, and the position signal generating means outputs a position signal whose magnitude increases according to the position of the cloth detector. If the position signal of the first storage unit is smaller than the position signal of the second storage unit, it is determined by the determining means that the work cloth is positioned on the right, and the position signal of the first storage unit is more than the position signal of the second storage unit. If so, it is determined that the work cloth is located on the left.

Effect As described above, according to the present invention, when there is an abnormality in the placement state of the work cloth, it is possible to let the operator notice the abnormality before executing the copy stitching, or stop the operation of the sewing machine. As a result, it is possible to avoid waste of time and thread due to meaningless execution. In addition, such an effect can be enjoyed also in an industrial sewing machine in which a work cloth is placed by an unmanned machine, for example.

Further, when the device of the present invention is applied to a sewing machine that changes the control of the sewing needle position according to the mounting state of the work cloth, the mounting state is automatically determined without the operator intentionally switching the control. The effect that the needle position control device can be switched is obtained.

Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 2, the sewing machine of the present embodiment has a sewing machine bed 10 having a flat upper surface (hereinafter referred to as bed 10), a pedestal portion 12 standing up from the right end of the bed 10, and the pedestal portion thereof.
An arm 14 extending cantilevered from the upper end of 12 and substantially parallel to the bed 10, and a head 16 provided at the tip of the arm 14.
A machine frame 18 composed of and is provided. The head 16 is provided with a main switch 20 for controlling the start and stop of the sewing machine, and the arm 14 is provided with a display plate 22 displaying a plurality of types of stitch patterns that can be formed by this sewing machine, and a stitch. A pattern selection switch 24 operated to select a pattern is provided. Further, the pedestal portion 12 is provided with a profile stitching switch 26 for performing profile stitching to form a stitch line at a certain distance from the cloth end, and a distance between the fabric end and the stitch line (hereinafter referred to as a seam allowance). Seam allowance setting operation member 3 operated for setting
0, needle swing adjustment operation member 31 and feed amount adjustment operation member 32
A warning light 33 and a needle raising instruction light 34 are provided.

FIG. 3 shows a state in which the cover of the head 16 is removed, and a needle bar base 36 is attached to a protrusion 35 fixed to the head 16 by a shaft 38 so as to be swingable in a vertical plane. A needle bar 40 is attached to the needle bar base 36 so as to be vertically slidable, and a sewing needle 42 is fixed to the lower end of the needle bar 40. The needle bar 40 is connected to a sewing machine motor (not shown) via a needle bar holder 44 and the like, and the needle bar 40 and the sewing needle 42 are driven by the sewing machine motor.
Can be reciprocated up and down. Also,
A needle rocking control motor (not shown) is connected to the needle bar base 36 via a Z-connecting rod 46 and the like, and the needle bar base 36 is rocked by driving the needle rocking control motor, whereby the sewing needle 42
The horizontal position of is changed within a certain range between the left end position and the right end position.

A cloth detector 54 is fixed to the needle bar base 36 on the operator side with respect to the center line of the sewing needle 42 so as to swing integrally with the needle bar base 36. The cloth detector 54 is a light emitting unit that emits infrared rays.
56 and the light receiving part that receives the reflected infrared rays
58 and. In the vicinity of the light receiving section 58, an optical filter 60 that allows the passage of infrared rays but blocks light of other wavelengths is provided.

An opening is formed on the upper surface of the bed 10, and the opening is closed by the needle plate 66. A plurality of slots are formed in the needle plate 66, and feed dogs 68 can be projected upward from the slots. The feed dog 68 is fed by a feed control motor (not shown) to feed the work cloth 70 in the front-rear direction in cooperation with a cloth presser foot (not shown). In this embodiment, the feed dog 68, the feed control motor, the cloth presser foot and the like constitute a cloth feed device. The needle plate 66 is further formed with a needle hole 72 that is long in the left-right direction, and the reflecting surface 74 is close to and parallel to the needle hole 72.
Are formed. The reflecting surface 74 reflects infrared rays emitted from the light emitting section 56 of the cloth detector 54 toward the light receiving section 58. The cloth detector 54 is provided with the center line of the sewing needle 42 and the needle plate.
It has the ability to detect a variation in the amount of reflected light from a detection area centered on a point that is diagonally forward to the right (operator side) by a fixed small distance from the intersection with the upper surface of 66 (hereinafter referred to as the needle drop point). If most of the detection regions are covered with the work cloth 70, the amount of light received by the light receiving unit 58 decreases, and the light receiving unit 58 is a detector that corresponds to the variation in the area of the detection region that is not covered by the work cloth 70. It is designed to output a signal.

FIG. 4 shows a control device of the sewing machine. The pattern selection switch 24 is shown in the upper left of the figure. A pattern selection counter 80 is connected to the pattern selection switch 24, counts the number of operations of the pattern selection switch 24, and supplies the count content to the stitch data generator 82. Further, although not shown, a plurality of light emitting diodes arranged on the display plate 22 are caused to emit light in accordance with the contents of the count, and the selected stitch pattern is shown.

The stitch data generator 82 stores the stitch data corresponding to each of the stitch patterns that can be formed, and selects the stitch data corresponding to the count contents of the pattern selection counter 80 from those stitch data. Feed calculation device 84 and needle swing calculation device 86
And to supply to. That is, the stitch data generating device 82 has one movement each time the needle bar 40 moves up and down once.
A timing pulse generator 88 for generating individual pulse signals is connected, and the stitch data generator 82 feeds feed data and needle swing data in the stitch data each time the timing pulse is supplied. It is supplied to the device 84 and the needle swing calculation device 86.

A feed amount adjusting device 89 is connected to the feed calculating device 84, and a needle swing adjusting device 90 is connected to the needle swing calculating device 86. The feed amount adjusting device 89 supplies the feed adjusting device 84 with feed adjusting data that changes according to the operation of the feed amount adjusting device member 32. The feed calculation device 84 multiplies the feed adjustment data by the feed data supplied from the stitch data generator 82, and the feed data supplied from the stitch data generator 82 is added to the feed amount adjuster member 32. After the change is made according to the operation position of, the feed drive control circuit 92 is supplied. Similarly, the needle swing calculator 86 is a stitch data generator.
The needle swing adjustment operation member 31 is added to the needle swing data supplied from 82.
The position corresponding to the position is changed, and then supplied to the needle swing control circuit 96 via the multiplexer 94. As a result, the feed drive control circuit 92 controls the feed control motor 98, the needle swing control circuit 96 controls the needle swing control motor 100, and the sewing needle 42
And the cloth feed amount by the feed dog 68 are appropriately controlled, and the stitch pattern selected by the operation of the pattern selection switch 24 is formed.

The copy stitching switch 26 is connected to a pattern selection counter 80 and a multiplexer 94. When the switch 26 is turned on, the pattern selection counter 80 is reset and the stitch data generator 82 performs straight stitch sewing. The eye data is output, and the multiplexer 94 supplies the output signal (scan control signal or needle position control signal) of the copy stitching control device 110 to the needle swing control circuit 96 instead of the output signal of the needle swing calculation device 86. It is switched to the state.

The copy stitching control device 110 outputs the sewing machine stop signal generator 112 that outputs the sewing machine stop signal when the cloth detector 54, the sewing machine motor is stopped, and the needle up signal when the sewing needle 42 is located above the bed 10. Needle up signal generator 11 for outputting
Equipped with 4. The output signals of the cloth detector 54, the sewing machine stop signal generator 112 and the needle up signal generator 114 are used to determine whether or not the work cloth 70 is placed on the left side of the sewing needle 42. Device 116 (hereinafter, determination device 1
16). Further, a trigger pulse generator 118 is connected to the discrimination device 116 so that a trigger pulse is supplied when the ON signal of the copy stitching switch 26 rises. As shown in FIG. 5, the discriminating device 116 is composed of a microcomputer including a CPU 120, a RAM 122, a ROM 124 and a bus 125, and the ROM 124 stores a cloth placing state discriminating program represented by the flowchart of FIG. Remembered That is, the discrimination device 116 is connected to the sewing machine stop signal generator 112, through the input port 126.
The cloth detector 54, the needle up signal generator 114 and the trigger pulse generator 118 are connected, and the warning light is output through the output port 128.
33, the needle-up instruction light 34 and the copy sewing multiplexer 1
30 are connected.

The copy stitching control device 110 also includes a variable resistor 132 that outputs a reference signal. The slider of the variable resistor 132 is moved by operating the seam allowance setting operation member 30. The output signals of the cloth detector 54 and the variable resistor 132 are supplied to a comparator 133, and the comparator 133 outputs a signal having a magnitude corresponding to the difference between these two signals through an A / D converter 134 and an adder.
Supply to 136. This adder 136 outputs the timing pulse generated from the timing pulse generator 88 to the OR circuit 13
The digital signals from the A / D converter 134 and the latch 140 are added every time the data is supplied via 8. Further, the same timing pulse is delayed by the mono-multivibrator 142 and supplied to the latch 140, and the latch 140 holds the content of the adder 136 as the needle position control signal according to the delayed timing pulse. There is.

The timing pulse generator 88 outputs the timing pulse only when the sewing machine motor rotates and the needle bar 40 reciprocates up and down, so that the timing pulse generator 88 is similar to the timing pulse even when the sewing machine is stopped. So that the clock pulses of
A clock pulse generator 144 is provided. However,
The clock pulse output from the clock pulse generator 144 is used only when the needle up signal from the needle up signal generator 114 and the sewing machine stop signal from the sewing machine stop signal generator 112 are input. 1
It is supplied to the adder 136 and the latch 140 via 38.

When performing copy stitching with the sewing machine configured as described above, the operator first places the work cloth 70 on the left side of the sewing needle 42, and the desired stitch formation position is substantially the center of the needle hole 72. Preset so that After that, when the copy stitch switch 26 is operated, the pattern selection counter 80 is reset, and even if any stitch pattern has been selected until then, the straight stitch is selected. Further, the multiplexer 94 is switched to a state in which the output signal of the copying stitching multiplexer 130 is supplied to the needle swing control circuit 96, and the state in which the copying stitching multiplexer 130 supplies the scanning control signal SCS of the determining device 116 to the multiplexer 94. Is switched to. As a result, the scan control signal SCS is supplied to the needle swing control circuit 96 via the multiplexer 94, and the needle swing control circuit 96 drives the needle swing control motor 100 by the direction and amount based on the scan control signal SCS. That is, the needle bar base 36
Is in a state of being swung based on the scan control signal SCS, and the swing causes the cloth detector 54 to pitch one pitch from the left end position to the right end position (in the present embodiment, the left end and the right end). The space between them is divided into 14 pitches).

In this state, the cloth detector 54 outputs a detector signal corresponding to the area of the part of the detection area not covered by the work cloth 70, and therefore the minimum value when the work cloth 70 is located in the entire detection area. The detector signal is output, and the detector signal having the maximum value is output when the reflecting surface 74 is located over the entire detection area. Then, the discriminating device 116 discriminates the placement state of the work cloth 70 based on the magnitude relationship of the scanning control signal SCS for which the maximum value and the minimum value are obtained.

The determination of the placement state of the work cloth is performed by executing the program represented by the flowchart of FIG. At the same time when the power is turned on, the process waits for an instruction to execute the copy stitch at step S1 (hereinafter, simply referred to as S1. The same applies to other steps). If the copy sewing switch 26 is operated and an ON signal is output and a dragger pulse is generated, the determination result in S1 is YES, and it is further determined in S2 whether or not the sewing needle 42 is in the raised position. For example, in S3, the needle raising instruction light 34 is turned on, and the operator is prompted to perform the needle raising operation. Sewing needle 42 is in the raised position,
If the needle up signal generator 114 outputs the needle up signal,
When the result of the determination is YES, and when the needle-raising instruction light 34 is already on, it is turned off in S4, and then S5 is executed.

In S5, the port of the copy stitching multiplexer 130 is set to P
Switched from a to Pb. The scanning control signal SCS, which is one output signal of the discriminating device 116, is switched to a state in which it is supplied to the multiplexer 94. Then, in S6, as a result of supplying the scanning control signal SCS that positions the needle bar base 36 to the left end to the copy stitching multiplexer 130, the needle bar base 36 is positioned to the left end, and the detector of the cloth detector 54 at this time. The signal is stored in the first register and the second register of the RAM 122 in S7, and together with this, the scan control signal SC at this time
S is stored in the third and fourth registers of the RAM 122 in S8. In the present embodiment, the scan control signal SCS is a signal that sequentially increases as the needle bar base 36 moves from the left side to the right side.

In S9, a signal for instructing to move the needle bar base 36 by one pitch to the right is supplied as the scan control signal SCS to the copy stitching multiplexer 130, and the lateral relative position between the cloth detector 54 and the work cloth 70 is determined. It is changed and the detector signal of the cloth detector 54 at that time is stored in the accumulator (hereinafter referred to as ACC) of the RAM 122 in S10. AC in S11
It is determined whether the value of C is smaller than the value of the first register, and if so, the value of the first register is the value of ACC and the value of the third register is the scan control signal SCS in S12. It is replaced, but if not, it is not replaced. Then, in S13, it is determined whether or not the value of ACC is larger than the value of the second register. If the determination result is YES, the value of the second register is ACC in S14.
, The value of the fourth register is replaced with the scan control signal SCS, but if the determination result is NO, the replacement is not performed. In the above steps from S9 to S14, the sewing needle 42 is located at the right end, and the determination result in S15 is YES.
Until the minimum value of the detector signal is stored in the first register, the maximum value is stored in the second register, and the minimum value of the detector signal is acquired in the third register. As the scan control signal SCS of the cloth detector 54, the scan control signal SCS of the cloth detector 54 when the maximum value of the detector signal is obtained is stored in the fourth register. In other words, the position signal of the cloth detector 54 when the entire detection area of the cloth detector 54 faces the work cloth 70 is stored in the third register, and the entire position of the detection area is processed in the work cloth 70 in the fourth register. The position signal of the cloth detector 54 in the state of facing the other portion (the reflecting surface 74 in this embodiment) is stored.

In S16, it is determined whether the value of the fourth register (non-working cloth position signal) is larger than the value of the third register (working cloth position signal). If the judgment result is NO, the work cloth 70
Is placed on the right side of the sewing needle 42, and the warning lamp 33 is turned on in S17, and the operator is warned that the follow-up sewing cannot be performed well. On the other hand, the value of the fourth register is larger than the value of the third register,
If the determination result is YES, the work cloth 70 is placed at the regular position on the left side of the sewing needle 42, so if the warning light 33 is already turned on in S18, it is turned off, and then S1
In 9, the port of the copy stitching multiplexer 130 is from Pb.
By switching to Pa, the needle position control signal is supplied to the multiplexer 94 instead of the scanning control signal SCS.

In this state, the cloth detector 54 supplies a detector signal corresponding to the relative position with the work cloth 70 to the comparator 133. Comparator 133
Compares this detector signal with the reference signal from the variable resistor 132, and outputs an error signal having a magnitude corresponding to the difference between them to the A / D converter 134, which the A / D converter 134 It is converted into a digital signal and supplied to the adder 136.

In this state, the sewing machine 42 has not yet been activated and the sewing needle 42 is in the raised position, so that the clock pulse generator 144
Clock pulse from AND circuit 146 and OR circuit 1
It is supplied to the adder 136 via 38. The adder 136 receiving this clock pulse adds the error signal from the A / D converter 134 and the digital signal from the latch 140. The result of this addition is held in the latch 140 after a certain minute time.

The digital signal held in the latch 140 is supplied as a needle position control signal to the needle swing control circuit 96 via the multiplexer 94, the needle bar base 36 is swung, and the position of the cloth detector 54 attached to it. Is modified so that the detector signal from its cloth detector 54 is equal to the reference signal from the variable resistor 132. For example, if the detector signal is greater than the reference signal, the cloth detector 54 is moved to the left with a movement amount corresponding to the difference between the two signals. Further, between the time when one clock pulse is supplied to the adder 136 and the time when the next clock pulse is applied to the adder 136, the needle bar base 36 is swung until the detector signal matches the reference signal. The period of the clock pulse is defined so that it can be obtained.

As a result of the detector signal being equal to the reference signal as described above,
The error signal from the comparator 133 is also zero, and the digital signal supplied from the A / D converter 134 to the adder 136 is also zero. Therefore, even if the adder 136 performs addition in response to the next clock pulse, the result is the same as the digital signal held in the latch 140, and the same digital signal as before is held in the latch 140 after a certain short time. The Rukoto. Eventually, the needle position control signal supplied to the needle swing control circuit 96 via the multiplexer 94 does not change, and the needle swing control motor 100
And the needle bar base 36 is kept stationary.

If the position of the needle bar base 36 is changed as described above, naturally the lateral position of the sewing needle 42 is also changed, and the position of the dropping point of the sewing needle 42 corresponds to the magnitude of the reference signal from the variable resistor 132. Becomes If this position is not the desired position, the operator operates the seam allowance setting operation member 30 to move the variable resistor 132
Change the reference signal from. Then, the same operation as that described above is repeated for the changed reference signal, and the position of the needle bar base 36 is changed, so that the position of the drop point of the sewing needle 42 is changed accordingly. When this position becomes the desired position, the stitch line is formed at the desired position by operating the main switch 20 to activate the sewing machine. The size of the stitch formed at this time is determined by the feed data supplied from the stitch data generator 82 and the feed adjustment data supplied from the feed amount adjusting device 89, as in the normal sewing operation. .

The work cloth 70 is sent along with the formation of the seam line, and the operator keeps the position of the cloth end almost constant in this process, but it is unavoidable that this changes to some extent. When the cloth edge position fluctuates in this way, the detector signal from the cloth detector 54 does not match the reference signal from the variable resistor 132, and the error signal from the comparator 133 is not zero. The signal is converted into a digital signal in the / D converter 134 and supplied to the adder 136. Since the timing pulse from the timing pulse generator 88 is supplied to the adder 136 via the OR circuit 138 during the operation of the sewing machine, the adder 136 receives the digital signal from the latch 140 and the A signal in response to the input of this timing pulse. The error signal from the / D converter 134 is added. After that, the same operation as described in the stop state of the sewing machine is performed, so that the detector signal from the cloth detector 54 matches the reference signal from the variable resistor 132.
The positions of 6 and the sewing needle 42 can be changed. Fabric 7 thus processed
When the position of the cloth end of 0 changes, the position of the sewing needle 42 is automatically changed so as to follow it, so the stitch line is always formed at a position at a substantially constant distance from the cloth end, The seam allowance is kept almost constant.

As is clear from the above description, in this embodiment,
The variable resistor 132, the comparator 133, the adder 136, the latch 140, the copying stitching multiplexer 130, the multiplexer 94, the needle swing control circuit 96 and the like constitute the copying control means, and the discriminating device.
A part for performing S1 to S15 of 116, a multiplexer for copy stitching
130, the multiplexer 94, and the needle swing control circuit 96 constitute a scanning unit, and the third register (second storage unit) and the fourth register (first storage unit) of the RAM 122 of the discriminating apparatus 116 further form a memory. I am configuring. Also, S6 of the discrimination device 116
And the part that executes S9 constitutes the position signal generating means,
The portion of the discrimination device 116 that executes S16 functions as a discrimination means.

In addition, in addition, in the present embodiment, it is necessary to determine the mounting state of the work cloth 70 because of the detection characteristic of the cloth detector 54. That is, since the cloth detector 54 outputs a detector signal whose size changes according to the area of the work cloth 70 existing in the detection area, the cloth edge should be located on the left side in the detection area. To the right, the detector signals of equal magnitude are output as long as the areas are equal. Therefore, the placement position of the work cloth 70 should be
42 and the left side are predetermined, and the magnitude of the detector signal and the cloth edge position are made to correspond to each other.

Further, in addition, S16 of the discrimination device 116 of the present embodiment is
An abnormal signal is generated when the magnitude of the work cloth position signal is not larger than the magnitude obtained by adding a constant value to the non-work cloth position signal. Therefore, even when the value of the detector signal does not change by a certain value or more because the work cloth 70 is not placed on the bed 10 or the light reflectance of the work cloth 70 is abnormally high, the same applies. An abnormal signal is generated, and the effect that such an abnormal state is also warned can be obtained.

In the embodiment described in detail above, the cloth detector 54 and the needle bar base 36 are driven by the common needle swing control motor 100, but the cloth detector 54 is separated from the needle bar base 36. It is also possible to use a control motor that is movable to and driven by a dedicated control motor. By doing so, even when the sewing needle 42 is located below the bed 10, the cloth detector 54 can be moved, and the time during which the cloth detector 54 can be moved to detect the cloth edge position is extended, and the detection can be performed. It can be done easily. In this case, the position change of the sewing needle 42 in order to follow the change of the cloth end position is performed until a temporary period while the sewing needle 42 is positioned above the bed 10, and thereafter the position change of the sewing needle 42 is prohibited. It

Further, in the above embodiment, the cloth placing state is determined based on the operation of the copy stitching switch 26.
It can also be performed based on the operation of a switch for determination other than that.

Further, in the above embodiment, the reference signal from the variable resistor 132 is emitted, and the seam allowance setting operation member 30
The formation position of the stitch line, that is, the seam allowance can be changed by changing the reference signal based on the operation of, but when the change is not necessary, a constant reference signal is always sent to the comparator 133. It may be supplied.

Further, in the above-described embodiment, the position of the sewing needle 42 can be changed according to the operation of the seam allowance setting operation member 30 even when the sewing machine is stopped. The clock pulse generator 144 and the AND circuit 146 can be omitted.

Further, in the above embodiment, the seam allowance setting operation member 30 is the sewing needle.
It is supposed to be operated while checking the position of 42,
It is also possible to set a scale indicating the seam allowance in the vicinity of the seam allowance operation setting member 30 and operate the seam allowance setting operation member 30 based on the scale to set the seam allowance.

Further, in the above-described embodiment, when the contour stitch is performed, the straight stitch is automatically selected. However, this is because the straight stitch is generally used for the contour stitch, and it is optional. It is also possible to perform the copy stitch with the seam pattern. In this case, the sewing needle 42 is positioned according to the stitch information for each reciprocation, and this positioning is performed by the cloth detector.
After positioning 54 at a position corresponding to the reference signal (hereinafter referred to as detector positioning), the position of the cloth detector 54 may be used as a reference. Alternatively, the movement amount of the sewing needle 42 may be determined from the detector signal, the reference signal and the stitch information relating to the current position.

In addition, in the above-mentioned embodiment, the warning light indicates an abnormal state of copy stitching.
The operator is instructed by lighting 33, but it is also possible to instruct by a buzzer or a display. The same applies to the needle lift indicator light 34.

Further, in the above embodiment, the control circuit except the discriminating device 116 is composed of a discrete circuit, but it may be composed of a microcomputer.

In addition, the configuration of the cloth detector 54 or the copy stitching control device 110 may be changed, or the lateral position of the sewing needle 42 may be changed by swinging the needle bar base 36 around a substantially vertical axis, or the zigzag sewing machine as a whole. It is possible to carry out the present invention in a mode in which various modifications and improvements are made based on the knowledge of those skilled in the art, such as changing the configuration.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the present invention. FIG. 2 is a perspective view schematically showing the outer appearance of a cloth edge copying sewing machine which is an embodiment of the present invention. FIG. 3 is a perspective view showing the head of the sewing machine with its cover removed.
FIG. 4 is a block diagram showing a control circuit of the sewing machine.
FIG. 5 is a block diagram showing a cloth placing state judging device of the sewing machine, and FIG. 6 is a flowchart showing a control program stored in a program memory of the judging device. 10: Sewing machine bed, 18: Sewing machine frame 36: Needle bar base, 40: Needle bar 42: Sewing needle, 54: Cloth detector 70: Work cloth 100: Needle swing control motor 110: Copy sewing control device 116: Cloth loading Stationary state determination device

Claims (1)

[Claims] 1. A cloth feed device for transferring a work cloth in a predetermined transfer direction in synchronism with vertical movement of a sewing needle, and a lateral line crossing the predetermined transfer direction at least at a time while the sewing needle is located above a sewing machine bed. A cloth detector which has a predetermined relative positional relationship with the sewing needle in the direction, and is movable in the lateral direction to detect the cloth edge of the work cloth extending in the predetermined transport direction, and the lateral position of the cloth detector is changed. A control motor that is driven to drive the control cloth and a scanning control unit that drives the control motor based on a detector signal from the cloth detector, and forms a continuous stitch along the cloth edge of the work cloth. In the cloth edge copying sewing machine, scanning means for driving the control motor before execution of the copying sewing in order to obtain the maximum value and the minimum value of the detector signal from the cloth detector, and a lateral side of the cloth detector. Position signal for directional position Position signal generating means for generating, a first storage unit for storing the position signal generated when the detector signal of the maximum value is obtained, and generated when the detector signal of the minimum value is obtained A memory having a second storage unit for storing the position signal and a magnitude relationship between the position signals stored in the first and second storage units, respectively, and the work cloth is left and right with respect to the dropping point of the sewing needle. A cloth edge copying sewing machine capable of judging a cloth mounting state, comprising: a judgment means for judging on which side the cloth is laid.